Function deriveSolanaKeyBytes

src/wallet.ts:66–91

(mnemonic: string)

 *   3. Final IL (32 bytes) = Ed25519 private key seed
 */
export function deriveSolanaKeyBytes(mnemonic: string): Uint8Array {
  const seed = mnemonicToSeedSync(mnemonic);

  // Master key from SLIP-10
  // @noble/hashes v2 requires Uint8Array keys (v1 accepted strings)
  let I = hmac(sha512, new TextEncoder().encode("ed25519 seed"), seed);
  let key = I.slice(0, 32);
  let chainCode = I.slice(32);

  // Derive each hardened child: m/44'/501'/0'/0'
  for (const index of SOLANA_HARDENED_INDICES) {
    const data = new Uint8Array(37);
    data[0] = 0x00;
    data.set(key, 1);
    // ser32 big-endian
    data[33] = (index >>> 24) & 0xff;
    data[34] = (index >>> 16) & 0xff;
    data[35] = (index >>> 8) & 0xff;
    data[36] = index & 0xff;
    I = hmac(sha512, chainCode, data);
    key = I.slice(0, 32);
    chainCode = I.slice(32);
  }

  return new Uint8Array(key);
}

/**
 * Derive both EVM and Solana keys from a single mnemonic.